The effect of salt and sugar on the freezing point of water
The hypothesis that a higher salt or sugar content in water will lower its freezing point has been proven to be true.
Water will normally freeze at 0 °C. However, seawater does not freeze at 0 °C, as the presence of salt lowers its freezing temperature to below 0 °C. The concept of freezing point depression is useful in applications where water needs to be kept liquid, especially in the use of antifreeze in combustion engines operating at freezing temperatures.
This science fair project may also be repeated by comparing the effects of salt and sugar on the boiling point of water.
The experiment may also be repeated using a different solvent, like alcohol or thinner.
Freezing point depression - http://en.wikipedia.org/wiki/Freezing-point_depression
Molar mass - http://en.wikipedia.org/wiki/Molar_mass